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It is known that modern mysticetes have teeth initially and then develop baleen plate germs in utero, but lose their dentition and have only baleen during their juvenile years and adulthood. However, developing mysticetes do not produce tooth enamel because at some point this trait evolved to become a pseudogene. This is likely to have occurred ...
Whales have two flippers on the front, and a tail fin. These flippers contain four digits. Although whales do not possess fully developed hind limbs, some, such as the sperm whale and bowhead whale, possess discrete rudimentary appendages, which may contain feet and digits.
They are one of two living groups of cetaceans, the other being the baleen whales (Mysticeti), which have baleen instead of teeth. The two groups are thought to have diverged around 34 million years ago (mya). Toothed whales range in size from the 1.4 m (4 ft 7 in) and 54 kg (119 lb) vaquita to the 20 m (66 ft) and 100 t (98 long tons; 110 ...
In terms of length, blue whales have often been compared to three school buses lined up back to back. These whales measure 90-100 feet long and are estimated to weigh from 200,000-352,000 pounds ...
The skim-feeders are right whales, gray whales, pygmy right whales, and sei whales (which also lunge feed). To feed, skim-feeders swim with an open mouth, filling it with water and prey. Prey must occur in sufficient numbers to trigger the whale's interest, be within a certain size range so that the baleen plates can filter it, and be slow ...
The two parvorders, baleen whales (Mysticeti) and toothed whales (Odontoceti), are thought to have diverged around thirty-four million years ago. [13] Baleen whales have bristles made of keratin instead of teeth. The bristles filter krill and other small invertebrates from seawater. Grey whales feed on bottom-dwelling mollusks.
The common name was chosen because the part of the tooth that protrudes from the gums (unlike the strap-like teeth of strap-toothed whales) has a shape similar to the tip of a flensing spade as used by 19th-century whalers. Despite the rather similar dentition, the spade-toothed whale and strap-toothed whale seem to be only distantly related.
Two stranded adult male strap-toothed beaked whales were recorded as only being able to open their mouths 3.2 cm and 4 cm wide, compared to females and juveniles that had a gape size of 6.5 cm. [7] It is thought male beaked whales use their teeth to compete for mating access to females, as evidenced by scars and scratches on the bodies of males ...